Repeated changes of dendritic morphology in the hippocampus of ground squirrels in the course of hibernation.

Quantitative Golgi study of hippocampal pyramidal neurons of ground squirrels showed rapid and profound transformation of their apical dendrites in the course of hibernation. The dendrites were significantly shorter, less branched and had fewer dendritic spines in the middle of hibernation bout than in the active euthermic ground squirrels between bouts. After arousal from torpor, within 2 h dendrites completely restored their structure. During hibernation, season remodelling of the hippocampal dendrites occurs repeatedly during each torpor-activity cycle.     

Entry into hibernation in M. Flaviventris: Sleep and behavioral thermoregulation

Hibernators of the genus Marmota (wt=3–5 kg) differ from smaller hibernators (wt<1 kg) in thermoregulatory characteristics during entry into hibernation. They might be expected to differ also with respect to the distributions of activity, awake and sleep states during entry. Marmots implanted stereotaxically with electrodes to record electroencephalograms and brain temperature (T_Br) were monitored remotely by a polygraph as well as video transmission as they entered hibernation. During entry, awake (A), slow wave sleep (SWS), and paradoxical sleep (PS) states could be identified. Activity which included nest building, grooming, and shivering slowed entry and became progressively more stereotyped as T_Br decreased. All animals exhibited at least one PS bout between T_Br=33?32°C. SWS as percent of total sleep increased (80 to 92%) as T_Br decreased from 35?25°C. This increase represented a decrease in number and increase in duration of SWS episodes. The length of individual SWS and PS episodes of the marmot did not differ from those reported in Citellus. These data suggest that entry into hibernation is a more complex phenomenon than merely an extension of slow wave sleep. Similar changes in arousal state distribution occur in hibernators of different sizes.     

Effects of exercise on energy balance in meal-fed mice

The effects of exercise on energy balance have been investigated in mice accustomed to eating their daily food ration in three meals. A meal period lasts 1 hour, and during that period mice were allowed to eat unrestrictedly a pelleted stock diet. Two series of experiments were conducted. In one series of experiments indirect calorimetric measurements were carried out in untrained mice that were assigned to 3 experimental groups; a first group of mice was allowed to rest; a second group of mice was exercised immediately before one of the 3 meals; a third group of mice was exercised immediately after one of the 3 meals. The exercise bout consisted of 1 hour of forced exercise on a rodent treadmill at a speed of 20 meters per minute. O2 consumption (VO2) and CO2 production were monitored throughout a full day except at the time the exercising animals were on the treadmill. In a second series of experiments long-term energy balance measurements were carried out. Mice were then assigned to experimental conditions similar to those previously described for 31 days during which period food intake and body weight were continuously monitored. At the end of 31 days of experiment, mice were killed, and their carcasses were individually analysed for their contents of energy, fat and protein. Carcass and food gross energy contents were assessed by bomb calorimetry. At the end of the long-term energy balance trial, the percentage of fat, the energy gain, the energy density and the weight of the dry carcass were significantly lower in exercised groups of mice than in the resting group of animals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Sleep and hibernation in ground squirrels (Citellus spp): electrophysiological observations.

Electroencephalogram (EEG), electrooculogram, electromyogram, and electrocardiogram were recorded from ground squirrels (Citellus beldingi and C. lateralis) during the summer and also during the hibernation season. Summer recordings revealed that the animals spent an average of 66% of the 24-h period asleep (49% of the 12-h light period and 84% of the 12-h dark period); 19% of the total sleep time (TST) consisted of rapid-eye-movement (REM) sleep, and 81% of TST consisted of slow-wave sleep (SWS). Recordings obtained during the hibernation season showed that hibernation was entered through sleep, but the distribution of sleep states was different than in euthermic sleep. During the early entrance when brain temperature (Tbr) was between 35 and 25 degrees C, the animals were asleep 88% of the time, but only 10% of the TST was spent in REM sleep. The EEG amplitude declined with decreased Tbr so that classical sleep stages could not be identified below a Tbr of 25 degrees C. The frequency of the EEG increased as Tbr decreased; but activity in the 0-4 cycles/s band occupied the majority of the record even at a Tbr of 10 degrees C. Below a Tbr of 10 degrees C the EEG was isoelectric except for intermittent bursts of spindles. It was concluded from these and other results that the entrance into hibernation represents an extension of the thermoregulatory adjustments that occur during SWS.     

Hibernating Little Pocket Mice Show Few Seasonal Changes in Bone Properties

Periods of disuse or physical inactivity increases bone porosity and decreases bone mineral density, resulting in a loss of bone mechanical competence in many animals. Although large hibernators like bears and marmots prevent bone loss during hibernation, despite long periods of physical inactivity, some small hibernators do lose bone during hibernation. Little pocket mice (Perognathus longimembris) remain underground during winter hibernation and undergo bouts of torpor and interbout arousals, but the torpor bout duration is shorter than other rodent hibernators. Additionally, little pocket mice may enter torpor during summer estivation. In this study, cortical and trabecular bone architectural, mineral, and mechanical properties were analyzed for femurs from little pocket mice captured during 8 different months (March to October) to determine seasonal effects on bone. There were no differences in any bone properties between the pre‐hibernation month of October and the post‐hibernation month of March, suggesting winter hibernation did not adversely affect bone properties. However, cortical area was higher in March than April, May, and June. Bone mechanical and osteocyte lacunar properties were not different between any months. Trabecular bone in the distal femoral epiphysis showed no changes between months. The distal femoral metaphyseal region showed higher trabecular spacing and lower trabecular number in May than August, otherwise, there were no differences in trabecular parameters. The few monthly differences in bone properties may be due to physical inactivity from periodic summer estivation or from the timing of birth and growth in spring and summer months. Anat Rec, 300:2175–2183, 2017. © 2017 Wiley Periodicals, Inc.     

Control of feeding in aplysia with ad libitum access to food: presence of food increases the intervals between feeding bouts

The patterning of feeding and the quantity eaten in Aplysia californica with ad libitum food access cannot be explained by the effects of three variables previously shown to control the patterning of consummatory feeding responses and the quantity eaten in animals hand-fed individual meals. Feeding in ad libitum conditions is regulated primarily by varying the time between feeding bouts rather than by modulating bout lengths or the efficacy of consummatory movements within a bout. Aplysia with steady-state food access are in a newly characterized feeding state in which they are relatively unresponsive to food. They eat very little (1-4% of the time), and the quantity eaten is unrelated to the quantity of food in the anterior gut. The steady state can be maintained by the presence of food, even if animals do not contact food. The chemosensory rhinophores signal the presence of food that maintains the steady state. Up to 24 h without food is needed for animals to recover from the inhibition of feeding by steady-state presence of food. Recovery from the steady state is partially governed by postingestion stimuli as shown by a faster recovery in animals that have not been in contact with food. Inhibition of feeding during the steady-state is mediated in part via humoral factors because bathing the cerebral and buccal ganglia in hemolymph from animals in the steady state inhibits the ability to elicit buccal motor programs via a cholinomimetic thought to simulate stimulation of the lips with food. After food deprivation that is sufficiently long so that the steady-state decays, animals eat a large meal the size and dynamics of which are consistent with regulation via the three variables previously identified. This large meal is modulated by pheromones secreted by conspecifics even in sexually immature Aplysia.     

Foraging behavior and physiological changes in precocial quail chicks in response to low temperatures

We examined whether low ambient temperatures influence foraging behavior of precocial Japanese quail chicks and alter the balance between investment in growth and thermogenic function. To test this, one group of chicks was exposed to 7 degrees C and one group to 24 degrees C during foraging throughout the developmental stage. Chicks adapted well to the temperatures through a high flexibility in behavior and physiological development. In response to cold, chicks shortened foraging bout lengths two- to sixfold, and increased cycle lengths (i.e. length of a brooding bout plus subsequent foraging bout), resulting in a decrease in total foraging time. Body temperature during foraging was lower in cold-exposed chicks but did not drop below 37.8 degrees C, suggesting that the direct cause to end a foraging bout was not body temperature. The metabolic rate of cold-exposed chicks was reduced by 48% to 60% when switching from foraging to brooding, which may be an important factor in determining foraging behavior of precocial chicks. Mass-specific food intake of the cold-exposed chicks exceeded that of warm chicks by 15%. Cold-exposed chicks doubled foraging efficiency to reach this intake during their reduced foraging time. Metabolic rates initially were similar in both groups, but increased rapidly and were elevated in cold-exposed chicks from 15 days of age onward. Growth rate initially was reduced in cold-exposed chicks, and exceeded growth of warm chicks only after 21 days of age. These results suggest that in response to cold, a shift occurs in the balance between growth rate and thermoregulatory function in favor of thermoregulatory function.     

Seasonal changes in leg strength and vertical jump ability in internationally competing ski jumpers

The aim of the present study was to investigate the effects of the seasonal changes in heavy strength training on maximal strength and vertical jump ability in internationally competing ski jumpers. A repeated-measures design was used to follow-up the changes in strength, vertical jump capacity, and neuromuscular efficiency (expressed as the ratio between squat jump height and the relative isometric force) in the ski jumpers. Measurements were performed in November (pre), January (middle of the competition season), and in March (end of the competition season). The weekly number of strength training sessions, absolute, and relative peak isometric squat force was significantly reduced during the competition period (p < 0.05). The body mass was reduced from pre-season to the middle of the competition season and remained at this level at the end of the competition season (p < 0.05). Squat jump height remained unchanged from pre-season until the end of the competition season (p < 0.05). Neuromuscular efficiency increased from pre-season until the end of the competition season (p < 0.05). The present study shows that maximal strength and body weight is reduced from pre-season to the end of the competitive season in internationally competing ski jumpers. The vertical jump ability did not change from pre-season to the end of the competitive season, while the neuromuscular efficiency increased during the competitive season. These findings indicate that coaches and athletes should emphasize adequate nutritional strategies and to apply a larger focus on strength maintenance training during the competitive season to maximize ski jump performance.     

Lipid peroxidation and antioxidant status in rat: effect of food restriction and wheel running

Using the activity-based anorexia model, the aim of this investigation was to explore antioxidant enzyme activity (catalase, superoxide dismutase), total antioxidant status (TAS), and alpha-tocopherol in blood, liver, and gastrocnemius muscle associated with the food restriction and voluntary wheel running during 8 days. In addition, lipid peroxidation was measured by measurements of malondialdehyde (MDA). Wistars rats (n = 56) were randomly assigned to one of four groups: an ad lib sedentary group, a control wheel activity group, a food restriction-induced hyperactivity group (1 h/day ad lib food, 23 h/day ad lib wheel access), and a food-restricted sedentary group. The animals were killed when the rats in the food-restricted group had lost 25% of their free feeding weight. Antioxidant enzyme activities and TAS in blood, liver, and gastrocnemius muscle were unaffected by voluntary wheel running. A wheel activity effect (P < 0.05) was obtained for the MDA concentrations in plasma, with lower concentrations in trained animals. Food restriction effects were obtained for antioxidant capacity in liver, as well as for CAT activity in the gastrocnemius muscle and plasma MDA concentrations with lower values in the restricted animals. On the other hand, the food-restricted rats showed higher plasma TAS concentrations (P < 0.05) and higher alpha-tocopherol concentrations in the liver (P < 0.05) when compared to animals fed ad libitum. Our results also showed that food restriction coupled to wheel running decreased antioxidant parameters in liver, and plasmatic MDA concentrations and increased TAS plasma concentrations when compared to the ad libitum sedentary situation.     

Food and light as entrainers of circadian running activity in the rat

The purpose of this experiment was to determine the extent to which circadian running activity could be controlled by two different environmental cues: periodic access to food and ambient light cycles. Seven male rats were successively exposed to the following four conditions: (1) With light cycles (LD 12:12) and continuous access to food, the animals displayed a basically nocturnal pattern of running. (2) With access to food for two hours during the illuminated portion of the LD cycle, all of the animals showed a burst of running preceding food presentation. Three of these seven animals concurrently showed diminished running associated with the light cycle. (3) The animals continued to run before the periodic presentation of food when constant light replaced the LD cycle. (4) When allowed continuous access to food, and still exposed to constant light, the animals continued to show bursts of running around the time that food had been delivered. Rats' circadian activity cycles were therefore influenced by periodic access to food. Moreover, when periodic food was offered during the illuminated portion of the LD cycle (when rats are normally inactive) food presentation was a more potent entrainer than photic cues in controlling running activity.     

Comparison of tracheal reconstruction with allograft,fresh xenograft and artificial trachea scaffold in a rabbit model

This study evaluated the possibility of tracheal reconstruction with allograft, pig-to-rabbit fresh xenograft or use of a tissue-engineered trachea, and compared acute rejection of three different transplanted tracheal segments in rabbits. Eighteen healthy New Zealand White rabbits weighing 2.5–3.1 kg were transplanted with three different types of trachea substitutes. Two rabbits and two alpha 1, 3-galactosyltransferase gene-knockout pigs weighing 5 kg were used as donors. The rabbits were divided into three groups: an allograft control group consisting of rabbit-to-rabbit allotransplantation animals (n?=?6), a fresh xenograft group consisting of pig-to-rabbit xenotransplantation animals (n?=?6), and an artificial trachea scaffold group (n?=?6). All animals were monitored for 4 weeks for anastomotic complications or infection. The recipients were sacrificed at 28 days after surgery and the grafts were evaluated. On bronchoscopy, all of the fresh xenograft group animals showed ischemic and necrotic changes at 28 days after trachea replacement. The allograft rabbits and the tissue-engineered rabbits showed mild mucosal granulation. The levels of interleukin-2 and interferon-γ in the fresh xenograft group were higher than in other groups. Histopathologic examination of the graft in the fresh xenograft rabbits showed ischemic and necrotic changes, including a loss of epithelium, mucosal granulation, and necrosis of cartilaginous rings. The pig-to-rabbit xenografts showed more severe acute rejection within a month than the rabbits with allograft or artificial trachea-mimetic graft. In addition, the artificial tracheal scaffold used in the present experiment is superior to fresh xenograft and may facilitate tracheal reconstruction in the clinical setting.     

Ventilatory pattern and chemosensitivity in unanesthetized,hypothermic ground squirrels (Spermophilus lateralis)

The present study examined the effects of severe hypothermia in the absence of anesthesia on breathing pattern, ventilatory control and chemosensitivity in a cold tolerant species capable of seasonal hibernation. Hypothermia was induced in ground squirrels and ventilation and heart rate were recorded in animals breathing air at a body temperature (Tb) of 5 and 10 degrees C. The animals were then exposed to hypercapnic (2, 4 and 6% CO(2)) and hypoxic (12, 10, 8 and 4% O(2)) gas mixtures. We found that severe hypothermia in ground squirrels caused the breathing pattern to change from a continuous pattern to patterns that are commonly observed during hibernation. This suggests that temperature and metabolism alone are important factors in producing these patterns. The relative ventilatory sensitivity to hypercapnia was retained in the ground squirrel during hypothermia while ventilatory sensitivity to hypoxia was totally abolished. This is in contrast to hibernation where a small but significant hypoxic ventilatory response is present along with an enhanced relative response to hypercapnia. This suggests that changes in Tb alone can not account for the changes seen in ventilatory sensitivity during hibernation.     

Effects of bulbectomy on hibernation,food intake and body weight in the european hamster,Cricetus cricetus

Bulbectomy was performed on European male wild hamsters in autumn, habitual phase of weight decline and entrance into hibernation. Total bulbectomy suppresses both nest building behavior and hibernation, and is followed by an immediate increase in food intake and obesity. The body weight curve of totally bulbectomized animals is in opposition of phase with that of the controls. Incomplete bulbectomy suppresses nest building behavior but hibernation is present with a diminution of periodic arousals. Hyperphagia starts in spring after the terminal arousal; it is similar to that of the total bulbectomized animals. Anosmic animals do not differ from the control animals.     

Biological assay of a novel quinoxalinone with antimalarial efficacy on Plasmodium yoelii yoelii

Compound 1-methyl-7-nitro-4-(5-(piperidin-1-yl)pentyl)-3,4-dihydroquinoxalin-2(1H)-one (VAM2-6) was evaluated against a blood-induced infection with chloroquine-sensitive Plasmodium yoelii yoelii lethal strain in CD1 mice in a 4-day test scheme. LD50 of the compound was 56.51 mg/kg and LD10 was 20.58 mg/kg (taken as the highest dose). Animals were treated by oral gavage of 20, 10, and 5 mg/kg. Mice in the untreated control group showed a progressively increasing parasitemia leading to mouse death on 6 days post-infection; in this group, all mice showed parasites in the blood on the fifth day of sampling; the mean parasitemia on that day was 19.4 %. A 4-day dosage of 20 mg/kg of VAM2-6 showed a 97 % chemosuppression of total parasitemia on the fifth day, a 28 days survival time, and 20 % of cured animals. A 4-day dosage of 10 and 5 mg/kg showed 85 and 37 %, respectively, chemosuppression of total parasitemia on the fifth day; but all mice died from days 6 to 9 post-infection with increasing parasitemia. Mice treated with chloroquine at 5 mg/kg survived during the experiment. The results obtained in this study showed that the infection outcome of P. yoelii yoelii-infected mice is affected by VAM2-6 compound by slowing down the parasite replication, retarding the patency time, and increasing their survival time. Although compound VAM2-6 was active at higher doses than chloroquine, these results leaves a door open to the study of its structure in order to improve its antimalarial activity.     

Effects of a competitive wrestling season on body composition, endocrine markers, and anaerobic exercise performance in NCAA collegiate wrestlers

Few data exist examining the body composition, endocrine, and anaerobic exercise performance changes over a competitive wrestling season. Eighteen NCAA wrestlers were tested for endocrine markers, body composition, hydration, grip strength, and power on four occasions: prior to pre-season training (T1); after pre-season training 3 days prior to the first seasonal meet (T2); mid-season one day prior to a meet (T3); and at the end of the season 2–3 days following the last meet (T4). Body mass, percent body fat (BF %), and fat mass were significantly lower (P ≤ 0.05) at T2 and T3 compared to T1 but were not different between T1 and T4. Lean body mass was significantly reduced at T2 only. Urine specific gravity was significantly elevated at T3 compared to T1, T2, and T4. Resting cortisol concentrations did not change but resting testosterone concentrations were significantly reduced at T2, T3, and T4. Maximal grip strength was significantly reduced at T2. Vertical jump peak power was significantly reduced at T2, T3, and T4. Wingate peak power was significantly reduced at T2 and T3. However, Wingate average power and total work did not significantly change. Fatigue rate during the Wingate test was significantly improved at T2, T3, and T4 compared to T1. In conclusion, body mass, BF %, and measures of peak force and power were reduced for most of the competitive wrestling season. Competitive wrestling reduces resting total testosterone concentrations throughout the entire season.     

Changes in serum cortisol reveal functional differences in frustration-induced chain chewing in pigs

The pituitary-adrenal correlates of oral stereotypes in pigs were studied in two frustration situations of intermittent food distribution in which small amounts of food were given every 4 min (n = 4), and a massed food situation in which the same total amount of food was given in one meal at the beginning of the session (n = 5). Control animals (n = 6) were exposed to intermittent food but without a chain. Both intermittent-food and massed-food pigs developed chain chewing at similarly high rates. Blood samples were taken on days 8 and 21 of the experiment. Serum cortisol decreased between the beginning and the end of session 21 in intermittent-food pigs, but increased in pigs subjected to the massed-food condition. These findings suggest that oral stereotypies elicited by an intermittent schedule of food presentation are not equivalent to those elicited by the massed-food regimen.     

Post vaccination follow-up of Brucella melitensis in blood stream of sheep by PCR assay

Brucella melitensis is the causative agent of brucellosis in sheep and goats. While there is no treatment of choice for brucellosis, vaccination with Rev1 vaccine in sheep is the only effective procedure to reduce the incidence of brucellosis in many countries. As it has been shown earlier, in cases with brucellosis, the agent enters into the blood stream at first and then localises in the reticuloendothelial system and reproduction organs. For this reason, and in order to determine the duration of presence of bacteria in blood, this research was carried out on 15 female sheep 3 months of age. Ten sheep were vaccinated with Rev1 vaccine and five were used as control (unvaccinated) group. Polymerase chain reaction (PCR) was used for amplification of the 720-bp sequence of immunogenic outer membrane protein gene specific to B. melitensis. Blood samples were taken before the beginning of the experiment and on the first, 7th, 14th, 21st, 28th and 60th days after that. PCR results showed that all animals were negative before the beginning of experiment, but on the first, 7th, 14th, 21st, 28th and 60th days after that, a positive reaction was observed in 50%, 100%, 100%, 90%, 70% and 50% of vaccinated animals, respectively. Also, 40% of the control group showed positive results only on the 14th day after vaccination. Some serological tests such as Rose Bengal test (RBT), serum agglutination test (SAT) and 2-mercapto-ethanol (2ME) were performed on samples which showed that both vaccinated and unvaccinated animals had titres for Brucella antibody in their sera on the 7th day with relative frequency of 70 and 20%, respectively. These findings show that bacteraemia may occur on the first day and prolongs until the end of experimentation with maximum presence on the 7th and 14th days after vaccination. Conversely, this can explain the B. melitensis dissemination ability from vaccinated animals to healthy ones.     

Feed efficiency in growth-retarded rats with ventromedial and dorsomedial hypothalamic lesions produced shortly after weaning

Weanling male rats received electrolytic lesions (L) in the ventromedial (VMN) and dorsomedial (DMN) hypothalamic nuclei; sham-operated rats served as controls. The animals were maintained for various periods up to 50 postoperative days on lab chow under standard conditions. In a short-term study, food intake and body weights were measured daily and body weight gain was divided by the food eaten to obtain the efficiency of food utilization. Also, gains in metabolic size ($\text{kg}\text{3}\text{4}$) were divided by food eaten. Both manipulations showed that DMNL rats, except for the first two postoperative days, utilized food normally. The same changes were obtained for weanling VMNL rats, except that they did not show a decline in utilization during the first two postoperative days. Computation of efficiency of food utilization for both VMNL and DMNL rats over postoperative durations ranging from 7 to 50 days showed that among 12 out of 14 experiments DMNL rats utilized food as well as controls. Out of 8 experiments, rats with VMNL utilized food better for weight gained than controls in one and poorer than controls also in one experiment; in reference to metabolic size they utilized food normally. The foregoing data, gathered from 225 DMNL, 64 VMNL and 181 control rats show quite convincingly that food utilization in both types of experimental animals is unimpaired despite profound reductions in ponderal and linear growth and food intake in the DMNL rat and reduced circulating growth hormone levels in the VMNL rat.     

Effects of milk consumption and deprivation on body fluids of suckling rats

Ten-day-old rats were separated from their mothers for 4 hours, allowed to suckle, and then separated immediately after this nursing bout. Plasma protein concentrations started to fall from deprivation levels by the end of the nursing bout, continued to decline for 30 min, and then gradually returned to deprivation levels $\text{3}\text{1}\text{2}$ hours later. Plasma sodium concentrations showed similar fluctuations after nursing, but these were not as rapid or reliable as those in plasma protein. Urine production increased steadily after suckling and by 4 hours after was highly correlated with milk intake during the nursing bout, indicating a relatively rapid disposal of excess fluids obtained from milk. Plasma volume (as measured by plasma protein or hematocrit) in pups kept at 30° or 35°C decreased by 4.6 or 8.3% within 2 hours following separation from the mother. Pups separated and kept at 35°C showed greater increases over time in plasma protein, urine production and weight loss than those kept at 30°C. The results indicated that body fluids, and particularly plasma volume, are highly labile in suckling rats; intravascular fluid volume decreases in a short time during the mother's absence, is restored quickly by nursing, only to fall again since the impact of milk consumption dissipates rapidly.     

Alcohol as a Food: A Commentary on Richter

The present study examined the maintenance of voluntary alcohol intake in male Long-Evans rats. A microstructural analysis of consummatory behaviors (food, alcohol, water) was carried out using a computerized drinkometer system. In this sample of animals, there was no association (r = 0.07) between total food intake and total alcohol intake. There was no compensation for the extra calories ingested in the form of alcohol via a reduction in total food intake, or a reduction in food bout sizes associated with pre- or postprandial alcohol consumption. Further microstructural analyses determined that there were no significant difference between water and alcohol in terms of their distribution in relation to food (non-, pre-, or postprandial bouts). Of the total of 586 bouts of fluid intake analyzed, 45.6% were consumed postprandially, with a similar number (43.2%) consumed nonprandially. A comparison of the size of food bouts associated with different fluid bout types (pre- or postprandial) indicated that food bouts were the same size regardless of whether they were accompanied by water or alcohol. A final analysis determined that 55% of the total daily alcohol intake was consumed postprandially, and that the sizes of non-, pre-. or postprandial fluid bouts were significantly different for water vs. alcohol. Post hoc pairwise comparisons found that alcohol postprandial bouts were significantly larger than all types of water bouts. Alcohol and water bouts ranged in size from <0.5 ml to >5.5 ml There was a significant difference in the distribution of bout sizes with more alcohol bouts at the high end of the distribution. Only 24% of the water bouts were >2.5 ml compared to 48.4% of the alcohol bouts. The results of this study demonstrate that rats organize their consummatory behavior in many discrete, short bouts. There were considerable individual differences in alcohol preference, alcohol-bout frequency, duration, and size, as well as the prandial distribution of bouts. All of these variables together produce the “pattern” of alcohol intake in individual animals, and is likely to influence the level of intoxication achieved. Although rats do not dissociate their alcohol intake from normal feeding patterns, alcohol bouts occurring postprandially are significantly larger than other bouts of fluid consumption, suggesting that animals perceive the pharmacological effects of and are affected by the alcohol they consume. In animals with a preference for alcohol solutions, it is unlikely that alcohol is consumed as a food.